Day of Year Calculator
Choose a date and see what day number of the year it is, how many days remain, and what percentage of the year has passed.
How to use the calculator
- Choose the date you want to find the day number for.
- The calculator shows which day of the year it is (January 1 = day 1), how many days remain, and what percentage of the year has passed.
What is this used for?
The day number of the year (also called ordinal date or "day of year") is used in programming, logistics, and some calendar systems. It's also a fun way to see how far into the year you actually are — or how much is left.
Leap years shift everything after February
1 March is day number 60 in an ordinary year, but day 61 in a leap year. Every date after February is therefore shifted by one throughout the rest of a leap year, while dates in January and February keep the same day number regardless. It is a small detail that becomes important as soon as day numbers are used to compare across years.
Day numbers are used particularly in agriculture, meteorology and astronomy, where the aim is to compare the same point in the season from year to year. That is precisely why the leap year shift is a genuine source of error: day 200 in 2024 and day 200 in 2025 are not the same calendar date, and a comparison that ignores this is really comparing two different points in the season.
Frequently asked questions
Does the calculator account for leap years?
Yes — in leap years, February 29 is counted, so dates after February get the correct day number based on a 366-day year.
What's the day number for January 1?
Day 1. December 31 is day 365 (or 366 in leap years).
Why is it sometimes called "Julian day"?
"Julian day" in this context (not to be confused with the astronomical Julian day number) is a common alternative name for the day-of-year number, widely used in older programming and logistics systems.